2014 Giant TCX full cable replacement, part 1: Preparation

In the past, I’ve written about the internal cable routing of Hyro, my 2014 Giant TCX SLR 2 cyclocross bike, as well as walked you through a rear shift cable replacement. However, I’ve never been able to give him a completely fresh set of cables and cable housings. Three and a half years in, he’s been long overdue.

One major reason was simply gathering the supplies and tools needed for the job.

If you’re even thinking of doing this job on your own, invest in a proper dedicated set of cable cutters. Unlike pliers, which can crush cables and housing, these will give you clean cuts by shearing action. I’m using Park Tool’s classic CN-10, which is highly recommended by a lot of mechanics. Jagwire, Pedro’s, Super B, PRO, and other tool makers have their own versions which should work just as well.

Park Tool’s guide to the different types of cable housing, with a cross section of each.

As great as TRP’s Spyre mechanical disc brake calipers are, they explicitly state that they work best with compressionless brake housing. Unlike traditional brake housing, which is spiral coiled along its length, the compressionless stuff more closely resembles shift housing in that it is made of multiple small wires in parallel that surround a plastic inner liner. In many varieties, what makes it compressionless is a woven layer of aramid fibers surrounding the whole thing. (One aramid variant is Kevlar, famously used in bulletproof vests.) This means compressionless brake housing is more resistant to bending, and must be routed as cleanly and with as few abrupt bends as possible.

There are Jagwire full cabling kits that carry their compressionless brake housing. However, they’re way too short for the full-length housing run required on many cyclocross bikes, and I don’t know any local bike shops that carry the “XL” version of these cabling kits – that would’ve worked.

Internally routed cables in a bike frame are a common bugbear of bike shop mechanics. There are many hacks out there that can help decrease the time sink and aggravation of fishing out cables and housing from inside a frame tube…but I say investing in a Park Tool IR-1 internal cable routing kit is the ultimate hack of all. I will be talking more about this tool in the future, but suffice it to say that it is AWESOME.

The final requirement is a set of ferrules, one each for 4 mm (shift cables) and 5 mm (brake cables). These are essentially caps that slip over the ends of the cable housings to prevent them from mushrooming outward. While brake ferrules can be made of plastic, shift ferrules are typically made of metal. On the 2014 Giant TCX, you will need six shift ferrules and four brake ferrules in total, and not all housing ends require them.

As you’ve no doubt picked up by now, preparation is crucial. I doubled up on it by buying shift cables, shift cable housing, and brake cable housing in bulk. I also have a couple road brake cable sets bought as spares. All that shift inner cable and cable housing should last me a few years; all I’ll have to replenish are brake cables and relevant ferrules when my supply runs low.

Finally, since full cable replacement involves removal of your handlebar tape, you might as well have a new roll of the stuff on hand. In a break from tradition, I tried Fabric’s knurl tape this time around.

In the next installment, I will walk you through the brake cable replacement.

How to improve your braking and deceleration

People don’t think too much of their brakes when riding their bikes, or even driving their cars. They usually relegate braking only for situations where you have to stop or slow down. Indeed, when learning how to operate any vehicle, braking is the least intuitive skill, and it deserves to be consciously studied and analyzed. Braking can actually unlock speed you never knew you had.

How well do you know how to use your brakes?

AS MUCH AS POSSIBLE, DO YOUR BRAKING IN A STRAIGHT LINE

Before we delve into the finer points of braking technique, we should look at the two finger-length pieces of rubber through which everything you do on a bike is transmitted: the tires’ contact patch.

Tires have a finite level of grip. At any one time, a rider can apply three forces to a tire: acceleration, braking, and cornering. The way tires work, they are able to do one of these three tasks to the theoretical limit of traction by committing 100% of their grip to that one task. However, they don’t do so great when asked to combine two tasks, because each task requires a certain portion of grip to work, and the tires have to split their grip between them. With this splitting of grip comes an according lowering of the traction limit.

This is why it’s best to do your braking in a straight line. Doing so lets your tires concentrate on deceleration, especially if you have to scrub a lot of speed rapidly. The moment you turn your handlebars, you will not be able to brake anywhere near as hard, because your tires’ grip will already be committed to cornering. The most you will be able to do mid-corner is to feather the brake levers, preferably the rear, as loss of front grip is almost impossible to recover from.

APPLY THE BRAKES SMOOTHLY

One other thing about tire grip: It doesn’t respond very well to sudden inputs. Smooth control inputs will maximize whatever grip you have available. This is one reason why you want to squeeze your brake levers progressively, and not grab them suddenly.

This smooth application is called “modulation.”

A disc brake offers much better modulation due to tighter tolerances and harder friction material.

By design, disc brakes have much better modulation than rim brakes, because the pads are harder and there is much less distance between them and the braking surface.

ON THE ROAD, THE FRONT BRAKE IS YOUR FRIEND

I’m pretty sure you’ve heard stories of people somersaulting over their handlebars because they used their front brakes. That will only happen if you’re clumsy with its use and application. Learn to love your front brake, because it is far and away the fastest way of retarding your speed.

If you tried to come to a stop with the rear brake alone, you’d need a lot more space. You can start by squeezing both brake levers equally, then learning to bias your braking more toward the front.

SHIFT YOUR WEIGHT BACKWARD

On a car, most of the braking happens on the front wheels. Because it has a pair of front wheels, the forward weight shift under braking translates only into the “dive” of the front suspension.

Maximum braking with rearward weight transfer on a road bike with drop handlebars.

With its single front wheel, maximum braking with the front brake on a bicycle requires active weight transfer. You do this by getting out of the saddle, leveling the pedals, and pushing your hips rearward, as far behind the saddle as you can. You’re effectively pushing the bike away from you as you brake. This will counteract any tendency to somersault forward.

Keep in mind that this weight-shifting technique should be done only in a straight line. If you initiate a turn with your hips shifted backward, you will end up unweighting and losing grip on the front wheel – and that is guaranteed to end with you hitting the floor.

PRACTICE YOUR MAXIMUM BRAKING

It’s worth going to a quiet street to practice this.

Sprint to 20 km/h or so, then squeeze your brake levers hard, remembering to perform your weight shifting. Maximum braking is achieved when your rear tire lifts a few centimeters off the ground, and skids when it meets terra firma again.

DECELERATION DOESN’T ALWAYS REQUIRE BRAKING

While pedaling at speed on flat terrain, the large wind resistance usually means all you need to shed some speed is to stop pedaling. Sitting more upright also increases your frontal area to the wind, increasing drag.

This is also important if you ride in a group. When in a paceline, you’re in close proximity to other riders and their wheels. A mistimed fistful of brake can mean collision within the pack. It’s better to control your speed by freewheeling and sitting up, very gently using the brakes if needed.

BRAKE EARLIER IN WET CONDITIONS

To work in the wet, rim brakes have to drive away water from the brake track first.

I cannot over-stress the importance of this tip for cyclists who ride bikes with rim brakes. Because of the closer proximity to the ground, the braking track of your wheels gets wet fairly easily. Your brake pads have to push this water away from the braking track before they stand a chance of generating friction and actually slowing you down.

To compensate for this, brake earlier than you normally would. It’s also a good idea to dry out your rims by periodically applying the brakes lightly while riding.

With disc brakes, the braking surface is much farther away and is less affected by water, so your braking is much more reliable. The limiting factor isn’t in the brake hardware, but in the grip of the tires. Because disc brakes also have much better modulation, however, you’re better able to make use of whatever tire grip and braking power you have.

TO GO FASTER, BRAKE LATER

Conversely, free speed exists for the taking if you can delay your braking as much as possible, while still remaining as smooth as you can on the levers.

This last tip requires practice and a healthy appetite for risk. On a course you know well, start entering the turns slowly. Then as your confidence builds, delay your braking point further and further, as you adjust your brake input to scrub off excess entry speed.

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I hope you learned something with this writeup. If you want me to write about a certain topic, let me know in the comments.

Adjusting a TRP Spyre mechanical disc brake caliper

It takes something special to unseat the established king of the hill. When it comes to mechanical disc brakes, the king was Avid’s BB7 single-piston design, and long it reigned supreme…until 2013. TRP, the high-end arm of Taiwanese brake parts firm Tektro, unleashed its Spyre disc brake caliper to the world and effectively usurped the BB7 from its throne.

Hyro’s Spyre rear disc brake caliper. To facilitate the twin-piston design, the actuation arm is a U-shaped stirrup that wraps around the top of the caliper body and pulls both pads from one cable.

So what makes the Spyre caliper so good? TRP essentially introduced a new twin-piston design, mimicking the action of a hydraulic disc brake caliper. The benefit isn’t in power, but in how much easier a mechanical disc brake system became to live with.

Periodic adjustment of a mechanical disc brake caliper is required because unlike their hydraulic cousins, the pistons don’t auto-compensate for brake pad wear. Adjusting a BB7 or a similar single-piston caliper requires setting the position of the “fixed piston” and the actuating piston separately – and these usually need to be reset every time the wheel is removed from the bike. With TRP’s brake, suddenly, there’s much less faff involved in the periodic adjustment to the brake calipers. In my experience the Spyre keeps its tune for longer, too, shrugging off wheel dismounts and remounts fairly well. In fact, adjusting a Spyre brake is so much easier to do compared to doing so on my folding bike’s V-brakes; when pressed for time, it can be as easy as turning a barrel adjuster.

While the barrel adjuster is the simplest way of adjustment, this also eats into the sweep range of the actuator arm and can reduce its leverage. TRP therefore recommends adjustment by setting the starting positions of the left and right pistons independently, and lessening the use of the barrel adjuster. To properly adjust a Spyre disc brake caliper, you will need the following.

• A workstand, display stand, or some other way of suspending the bike
• Long hex keys/Allen wrenches: 3 mm and 5 mm
• Paper towels
• Isopropyl alcohol

Start by suspending the bike off the floor. As long as you have the capability to spin the wheels freely, any kind of workstand or display stand will do.

I use a Minoura DS-30AL display stand and a wall to suspend both wheels so they can spin freely.

CLEAN THE BRAKE ROTORS

The first thing to do as part of maintenance is to clean off your brake rotors. Squirt some isopropyl alcohol into a paper towel and wipe it on both sides of the brake rotor. This will clean off oils, dirt, and brake pad material on the rotor’s faces. Alcohol is volatile, so after your once-over with the paper towel, any residual alcohol will evaporate on its own fairly quickly.

Because this cleans off the rotor faces, including some built-up brake pad material, you may want to perform a bed-in procedure on your rotors afterward to quiet down any brake squealing.

RESET BRAKE CABLE TENSION AND ACTUATION ARM PRE-LOAD

Wind in the barrel adjusters on the brake calipers first all the way (clockwise), then back them out two full turns (counterclockwise) so you have enough room for adjustment.

Hyro’s Spyre front disc brake caliper. Seen at the bottom are the chrome silver actuation arm, set to its correct pre-load, and its black pad adjuster. At the other end is the plastic barrel adjuster.

With your 5 mm hex key, undo the cable anchor bolt from the actuation arm. Pull the cable tight, then push the actuation arm in slightly to pre-load the caliper and remove any slack or “dead spot” in its travel. In my experience, this is usually just the first 3 or 4 degrees from the actuation arm’s fully relaxed position, or enough to cover one of the caliper body’s side bolts halfway. Once pre-load is set, tighten the cable anchor bolt. If you have a torque wrench, crank it up to 5 Nm.

Testing the adjustments for the front brake by spinning the wheel and squeezing the left brake lever.

Test the adjustment by squeezing the brake lever. You may find that the lever sinks a little too close to the bar. As long as the brake lever doesn’t contact the bar itself, that’s okay. The rest of the adjustment procedure will involve the use of the pad adjusters on the sides of the actuation arm.

SET PAD POSITION

Brake pad adjuster on the non-drive side. The hole is partially obscured by my front fender stay, but the hex key still fits right in.

Take your 3 mm hex key and insert it into the black holes on either side of the actuation arm. These are the pad adjusters. Make sure the hex key bottoms out into the adjuster.

The pad adjusters work by moving the brake pads closer to the rotor when turned clockwise. It’s best to adjust by small increments – a quarter-turn at a time, at the most. Test the pad spacing by spinning the wheel and listening for any rotor rubbing. If there is any audible rubbing, back out the pad adjusters until the rotor quiets down.

It’s entirely possible for the pad adjuster on one side to be set too far away from the rotor while the other is set too close. That usually means only one pad is doing the lion’s share of the deceleration work, effectively flexing the brake rotor one way with no counter-force, and is wearing away far quicker than its opposite number. The pads should be adjusted so they share braking loads and are balanced in wear rate.

While adjusting, periodically check the clearances from rotor and brake pad – by eye, by ear, and by lever feel.

Another view of the pad-to-rotor clearance.

Test the adjustment by squeezing the brake lever again. Because the Spyre is cable-actuated, the rider can tune the feel and bite point of the brake lever to his/her preference. In the interest of brake lever modulation, I suggest setting the bite point around the first 15-20% of the total lever travel. Setting the bite point too high sacrifices modulation (one of the Spyre’s strong suits), and more readily induces wheel lockup and skidding. Too low, and you may end up pulling insufficient cable for emergency braking situations.

Once you’re satisfied with the braking power and lever feel, you’re done. Test your adjustments by riding around in a controlled area.

UPDATE 20180604

Lance left a pretty helpful suggestion on the comments section of my post on TRP Spyre brake pad replacement:

The other day I was adjusting the 3 mm screw, and found that if I used a 0.2mm feeler gauge [a tool used for measuring valve clearances on engines – Ed.] between the pads and the rotor on both sides, I could get a pretty accurate clearance, the same on both sides of the rotor. I didn’t need to guess if I had turned one screw more or less than the other, and got good results on brake lever pull. Probably could use a business card [as substitute for a feeler gauge]. I adjusted one side at a time. It’s not the folded business card trick for centering the caliper, it’s when you’ve already locked down the caliper and adjusting each pad.

TOOL-FREE ADJUSTMENT WITH THE BARREL ADJUSTER

Turning the barrel adjuster counterclockwise (orange arrow) will pull the cable, effectively shortening the range of travel of the actuation arm (red arrow).

If you’re pressed for time and have no tools on hand, a quick way of adjusting the Spyre’s brake pads is by the familiar barrel adjuster. Backing out the barrel adjuster by turning it counterclockwise brings the pads closer by increasing the pre-load on the actuator arm. As before, listen for rotor rubbing. If it happens, wind the barrel adjuster in clockwise to decrease pre-load and spread the pads away from the rotor.

If your calipers’ pad adjusters were set correctly, you’ll find that small adjustments at the barrel adjuster are all you should need to compensate for pad wear. If more than five full turns of the barrel adjuster were needed to cinch up the braking action, that’s a sign that the caliper’s pad adjusters are set too far away and need to be re-tuned.

Next time, I’ll show you the process of removing and replacing brake pads from a Spyre caliper.